ATC SCM40 - £3,275

In the SCM40, ATC has a sizeable floorstanding loudspeaker that's set way away from the fray, says David Price

There’s something odd about ATC’s SCM40 – it doesn’t look or feel like almost any other loudspeaker in its price class. It’s almost as if someone has forgotten to style it, like they’ve taken three drivers and put them in a box designed to do the job and then gone home. This is in marked contrast to many rivals, which have all kinds of stylistic flourishes. Despite looking rather ‘old school’ – albeit in a timeless sort of way – the SCM40 is actually a new model that came out in 2013, replacing a 2007 design of the same name that looked as if it had been launched in 1988! ATC, it seems, doesn’t pay too much attention to matters of fashion.

Construction quality is another matter. There is absolutely nothing about this speaker to suggest it is built to its price, and you’re reminded of this when you try to move it. The drive units look highly anachronistic, and that’s because they are – especially the midband driver. The Gloucester company began its life building drive units for professional monitor speakers, and then started making its own. Founder Billy Woodman seems as fascinated by transducers as he was 40 years ago when ATC was born, and it has a dome mid unit unique to this marque.

Very few companies make midrange domes these days, because they’re hard to get right. Instead, most prefer to use a small version of a coned bass driver to handle these frequencies. The benefit of a dome, as well as excellent dispersion, is that it is phase-coherent with the dome tweeter – which is to say it radiates sound waves in a similar manner. This brings excellent integration to that critical tweeter/midrange driver relationship, and you can hear it in every speaker so designed, from the classic Yamaha NS-1000M to the SCM40. This 75mm soft dome mid driver uses a hand-doped acrylic diaphragm and suspension system, using a “secret ATC formula”. It mates to an ATC-designed and built 25mm dome tweeter with a doped polyester diaphragm and suspension, with alloy wave guide. The bass driver is 164mm in diameter and features a hand coated paper pulp diaphragm, chosen for its balance of low mass, damping and rigidity, and there’s a huge motor assembly behind.

A three-element crossover is fitted, comprising a low pass filter, band pass filter and high pass filter. The efficiency of the system is set by the bass driver with the mid and HF padded down accordingly, the company says, so it’s kept as simple as possible – this is achievable because the drivers are designed around it. As with all ATC three-ways, the crossover points are 380Hz and 3.5kHz. One problem with this speaker is that it’s not particularly easy to drive. ATC says its impedance curve is flat, so the amplifier shouldn’t require Herculean reserves of current, but it sure does need watts! Quoted sensitivity is low for a big box – 85dB/1W/1m – which means over 60W is the order of the day. I try several solid-state amplifiers and all get hot and slightly bothered at very high volumes. This is in part because ATC has gone for an infinite baffle cabinet, which asks more from whatever is driving it.

Sound quality

There are too many loudspeakers describing themselves wishfully as ‘studio monitors’, but here we have something that is far closer to this than most. The big ATC is unerringly revealing of what you put into it, and certainly doesn’t sugar the pill. But if you imagine that it is cerebral, analytical and dispassionately forensic then think again. Feed it a high-quality source via a smooth, punchy solid-state amplifier and you get a startlingly fine sound back.

In essence, you get a large, wideband sound that’s starker and more open than anything else I’ve heard at this price. This is made more apparent by its superb bass; arguments rage about the relative merits of infinite baffle boxes, but ATC has got this one working brilliantly. The only downside is that it makes lesser amplifiers feel like a jogger running in concrete trainers!

Kraftwerk’s Tour de France Soundtracks is breathtaking – rarely have I heard its low frequencies in such sharp relief. Positioned just 30cm from my rear wall and toed-in slightly, the speed, power and grip is superlative – it easily outdoes more expensive big boxes like Spendor’s D7 or Sonus faber’s Olympica II. The attack transients on the synth bass are superb, starting and stopping with the speed of an LED. On songs with vast tracts of low frequencies such as the Moog bass on 4hero’s Cosmic Tree, the bottom end is rock solid, prodigious and ultra tight, but give it an indie guitar track like REM’s Maps and Legends and the speaker is relatively circumspect. Basically, it tells you what’s going on if it is going on, and if it isn’t then it doesn’t! This is the mark of a serious wideband monitor loudspeaker, and a reminder that so many reflex ported designs simply aren’t doing bass right. Conventional-holed boxes have practicality and ease-of-drive in their favour, but can bring problems related to phase integrity across the whole frequency. This often means the bass can sound like it’s a fraction of a second behind.

Not so the SCM40, and the way it integrates its superb low frequencies with the midband is a joy; in this region it’s more searching than many, but is never harsh unless the source and/or song is too. It sounds like a veil has been lifted from in front of the music and it gives an explicit insight into the proceedings. I am impressed by how deep it digs into Thomas Dolby’s Airwaves; it ekes its way into the groove and throws out loads of info. It sets up an accurate stereo soundstage and hangs images back when needed, but projects well when called upon. It proves highly coherent in its handling of phase, everything snaps into focus and arrives at the right place and time.

Despite that big, prodigious bass, you would not call the ATC warm. It has quite a revealing balance that isn’t afraid to ‘do’ bright when the recording and/or ancillaries dictate. Treble is airy, spacious and well etched. The looped hi-hats on Beatmasters Who’s In The House? are crispy and scratchy, which is just how they should be. There’s no gilding of the lily with the SCM40, everything is handed to you in an accurate and unalloyed way. Some may find it bright; it’s certainly a fearless critic of your ancillary components, so if you’ve got some £1,000 separates and you’d like to buy the ATCs to partner them until you’ve saved up for better, you should be prepared to be reminded why you need to save up!

In practical terms, this is the biggest problem – they are too revealing for most front ends and certainly those in their price class. Most buyers with this sort of money will not want something that tears into recordings  in such a way. Play some classic Blue Note jazz in the form of Lou Donaldson’s Alligator Bogaloo, and it’s wonderfully sonorous and insightful, swinging along like you wouldn’t believe. But move to the Byrds’ Eight Miles High (recorded around the same time) and it sounds disappointingly thin and insubstantial; it’s still musically enjoyable, but doesn’t half sound poorly recorded.


Given a serious source and recording, the new ATC SCM40 is superb – I know of no price rivals that give this level of accuracy, speed and insight. It strings the rhythmic elements of the mix together brilliantly, punching out subtle dynamic inflections in a marvellously satisfying and visceral way. But then again it will have you fretting about how best to drive it for years to come, because you know it’s capable of a level of transparency you’d normally only expect from loudspeakers at three or four times its price. It’s certainly a great speaker to commit to and build a system around – but if you’re looking for something that’s simply going to make ‘a nice noise’ regardless of partnering equipment and recordings, then others are certainly going to be a more appropriate match.

LIKE: Superlative clarity; excellent phase coherence; sublime bass
DISLIKE: Hard work for an amplifier; too revealing for most 
WE SAY: A great modern monitor loudspeaker, but not for all

TYPE 3-way floorstanding loudspeaker
DIMENSIONS (WxHxD) 265 x 980 x 300mm
• Infinite baffle cabinet design
• 25mm soft dome tweeter
• 75mm soft dome midband driver
• 164mm bass driver
DISTRIBUTOR ATC Loudspeaker Technology Ltd
TELEPHONE 01285 760561